Heretofore cardiac pacing lead assemblies have generally comprised an electrode and a flexible insulated conductor for connecting the electrode to a cardiac stimulator. The electrode is introduced through the vascular system into a cardiac cavity and is moved into a position to contact the endocavitary wall of the heart. Various types of attaching devices have been utilized to maintain the electrode in a fixed position with respect to the wall to be stimulated. For example, fins and tines on the electrode have been utilized to interlock in the trabeculae within the heart in order to prevent dislodgement of the electrode. With any type of electrode attaching device, there is some probability that the electrode will become displaced from the wall of the heart due to the constrictions of the heart with each heart beat. Accordingly, cardiac pacing electrodes have been designed to positively attach to the wall of a heart. For example, electrodes may include anchoring devices such as fishhook shaped barbs or pinching wires. If the pacing lead and electrode are to be subsequently removed, as is the case when a patient only requires cardiac pacing following an operation, it is desirable that the electrode be removed without risk of damage to the wall of the heart.
One proposal for enabling a cardiac stimulation probe to be anchored firmly in the endocavity wall until the natural formation of fibrosed tissue ensures securement of the probe in place is with the use of a harpoon shaped anchor situated at the end of the probe and made of a solid, biologically compatible or of a material which can be resorbed during a period on the order of three weeks to three months. Such an endocavitary cardiac stimulation probe is disclosed in U.S. Pat. No. 4,258,724.
As will be described in greater detail hereinafter the present invention provides a temporary pacing lead assembly which differs from the previous assemblies and which may be positively affixed to the endocavitary wall of an organ to be stimulated, but which may also be readily removed at any time, without requiring resorption of the anchoring member, from the wall without creating local damage to the portion of the wall where the lead is attached.